后牛顿力学及其应用

本文综述了牛顿重力理论的近代发展,即后牛顿力学或度规理论,並简述了它的现代应用成果。     

有多余坐标完整系统的Hojman守恒量

研究有多余坐标完整系统的Hojman守恒量．给出系统Lie对称性与Noether对称性，Lie对称性与形式不变性间的关系．得到特殊Lie对称性、Noether对称性以及形式不变性导致的Hojman守恒量．举例说明结果的应用．     

Experimental Study of Structure Shock Vibration in Soil Caused by Explosion of Conventional Weapons

When hitting underground structures directly or exploding in rock-soil media near underground structures, the conventional weapons with large charge weight will make underground structures be subjected to strong shock vibration and cause personal casualty and damage of precision electronic equipments. The shock vibration has become one of the cardinal killing means of weapons. However, the existing methods of predicting structure shock vibration are limited evidently. In this paper the coupling coefficient of acceleration in clayey soil is obtained firstly. Subsequently based on repeated experiments of chemical explosion, after dimension analysis and by using method of multivariate stepwise regression, the calculation formulae of shock vibration acceleration for the underground structure are obtained finally. The formulae consider top and side explosion respectively, taking into account the effects of penetration depth, charge weight, distance to explosion center, rock-soil media, size of structure and buried depth. They are easy to use with high practicability and degree of confidence, and can provide credible evidence for prediction of shock vibration and vibration isolating design of underground structure.     

20世纪物理学对人类社会的深刻影响

相对论和量子力学奠定了20世纪近代物理学的发展基础，相继取得了人们在原子能、航天、激光、超导、信息、纳米等一系列现代高新技术的广泛应用，对人类社会产生了深刻的影响；近代物理学发展的特点是向“微观世界”和“宇观空间”进军，向“新事物”和“复杂性”进军，形成了从基础性研究到促进高新技术应用的新发展模式；物理学发展的基本观点是“彻底唯物”和“批判性”的，物理学理论体现了“简单、对称、和谐”的美。     

液固两相槽道流中柱状粒子取向的数值研究

对柱状粒子在槽道流场内的运动进行数值模拟，然后用统计方法得出大量柱状粒子的取向分布；给出了粒子长径比、粒子密度和流场区域对粒子取向分布的影响．计算结果表明，柱状粒子长径比的变化对粒子取向分布的影响不明显，粒子密度对粒子取向分布有一定影响，而流场区域所造成的流场横向速度梯度对粒子取向分布有重要影响．随着流场横向速度梯度增大，粒子取向趋势愈加明显，且当流场横向速度梯度增大到一定程度时，粒子取向都趋向于流动方向．文中部分结果与相关实验进行了比较，两者定性吻合较好。     

坚持对标对表 秉持优良传统 建强力学领域“国家队”

中国科学院力学研究所（以下简称“力学所”）作为我国力学领域的“国家队”，是一支重要的国家战略科技力量。新时期、新要求，明确力学所的使命、责任和目标，为国家作出重大贡献，是建强“国家队”的基本要求。为此，文章对标对表“充分体现国家意志、有效满足国家需求、代表国家最高水平” 3个方面要求，阐述了力学学科及力学所发展历程与国家重大需求的关系，分析了力学领域“国家队”的特征与使命任务、新征程中面临的新形势和新挑战，对如何建设好力学领域“国家队”提出了构想与举措。     

Microwave-assisted synthesis, anticonvulsant activity and quantum mechanical modelling of N-（4-bromo-3-methylphenyl） semicarbazones

Objective： To study the effect of halo substitution on disubstituted aryl semicarbazones on the anticonvulsant potential and model the activity based on quantum mechanics. Methods： A series of twenty-six compounds of N^4-（4-bromo-3-methylphenyl） semicarbazones were synthesized and evaluated for the anticonvulsant activity in the maximal electroshock seizure （MES） and subcutaneous pentylenetetrazole （scPTZ） seizure threshold tests. Some potential compounds were also tested in the subcutaneous strychnine （scSTY） and subcutaneous picrotoxin （scPIC） seizure threshold tests. The synthesized compounds were tested for behavioral impairment and CNS （central nervous system） depression in mice. Quantum mechanical modelling was carried out on these compounds to gain understanding on the structural features essential for activity. Results： Some compounds possessed broad spectrum anticonvulsant activity as indicated by their effect in pentylenetetrazole, strychnine, picrotoxin and maximal electroshock seizures models in resemblance to other aryl semicarbazone derivatives reported earlier. The higher the difference in HOMO （highest occupied molecular orbital） and LUMO （lowest unoccupied molecular orbital） energy levels was, the greater was the activity profile. Conclusion： The pharmacophoric requirements for compounds to exhibit anticonvulsant activity that includes one aryl unit in proximity to a hydrogen donor-acceptor domain and an electron donor have been justified with the molecular orbital surface analysis of the synthesized compounds.     

基于Maple的理论力学教学实践

利用Maple强大的符号与可视化功能,方便、快捷、形象、直观地求解了理论力学中的几个具体问题,实现了基于Maple的理论力学可视化教学.Maple在数值计算和数据可视化方面具有较强的能力和特色,能简单、快捷地处理理论力学中自由落体偏东微分方程的求解,有限长度线段引力场的场强和引力势的计算问题,并同时绘制出数值解的2D、3D图形.列举了傅科摆的运动轨迹、洛伦茨方程求解计算的可视化结果,给出了洛伦茨方程求解的Maple程序.具体实例表明,用Maple来完成微分方程的求解和数值计算,实现复杂运动过程和计算结果的形象直观化,便于对各种初始条件下各变量的关系进行比较分析.对于物理教学提供了一种方便、快捷地实现可视化教学的方法.     

基于Pro/ENGINEER开发的材料力学仿真实验系统

基于Pro/ENGINEER的三维实体造型、装配模拟、机构运动仿真等功能开发了材料力学仿真实验系统,使抽象、复杂的教学内容变得生动、形象、直观,提高了实验教学效果。     

神奇的土颗粒与土力学实验教学改革

基于土力学实验特点及教学现状的分析研究,重点探讨了目前实验内容设置和实验教学模式.针对其不足对土力学实验教学进行改革,包括更新实验内容,改革教学模式,以教学演示仪器及土颗粒神奇现象等方式吸引学生,从而提高了土力学实验教学水平,激发学生兴趣,培养了学生创新能力和科研素质.